The site and mechanism of prostaglandin transport between intraocular fluids and blood in the normal and inflamed eye will be studied. In addition, we will study the effect of uveitis on the concentration of other chemical constituents of these fluids. The major goal of these investigations will be to define the physiological effects of uveitis. Prostaglandin transport will be studied in vivo by measuring the rate of He-PGE1 elimination from the vitreous body and in vitro by measuring the uptake of H3 equals PGs by the anterior uvea from the incubation medium. These in vitro studies will also include a a characterization of the prostaglandin uptake mechanism in terms of competitive inhibition, metabolic and ionic requirements, etc. In addition to the anterior uvea, this in vitro study will include the choroid plexus, kidney cortex and liver slices and rabbit uterus in order to characterize prostaglandin biotransport in more general terms. Studies on the effects of uveitis on the chemical composition of the intraocular fluids will include, in addition to ascorbate and protein, Na ion, K, Ca, Mg ions, glucose and lactate. The concentration of these substances will be estimated in both the aqueous and the vitreous humors of normal and inflamed eyes and in blood plasma. Special attention will be paid to the possible effects of uveitis on active secretory processes, i.e. effects of uveitis on the intraocular concentration of substances which are normally secreted into the intraocular fluid compartment.